Conventional high frequency switches such as antenna switches include a microwave switch disclosed in Japanese Patent No. 2532122 and a transmission and reception switching device disclosed in Japanese Patent No. 2830319, for example.
The microwave switch disclosed in Japanese Patent No. 2532122 has PIN diodes inserted in series and parallel in a signal line. Forward currents are passed through the PIN diodes to turn them on, and the PIN diodes are reversely biased to turn them off, thereby switching between high frequency signals.
The transmission and reception switching device disclosed in Japanese Patent No. 2830319 employs a circuit scheme wherein a switch is constructed of transmission lines and PIN diodes or the like which are connected in series to the transmission lines, the transmission lines and the PIN diodes being connected parallel to a signal transmission line.